autofs-5.0.6 - add disable move mount configure option

From: Ian Kent <ikent@redhat.com>

With the introduction of systemd the root filesystem is now usually
marked as shared instead of private as part of the systemd sandbox
functionality. As a consequence moving a mount from one mount point
to another is not allowed.

To resolve this a configure option (--disable-move-mount) to disable
autofs preparing mount tree and then moving it into place has been
added. The move mount use in autofs was needed for a small set of
automount types with older kernels (prior to 2.6.39). So to disable
the use of move mount it's necessary to use a recent kernel.
---

 CHANGELOG           |    1 +
 autofs.spec         |    2 +-
 configure           |   18 ++++++++++++++++++
 configure.in        |   10 ++++++++++
 daemon/automount.c  |   11 +++++++++++
 include/config.h.in |    3 +++
 modules/mount_nfs.c |    5 -----
 modules/parse_sun.c |   40 +++++++++++++++++++++++++++++++++++-----
 8 files changed, 79 insertions(+), 11 deletions(-)


diff --git a/CHANGELOG b/CHANGELOG
index 304b6a2..c682f94 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -12,6 +12,7 @@
 - fix wait for master source mutex.
 - fix submount shutdown race.
 - fix fix map source check in file lookup.
+- add disable move mount configure option.
 
 28/06/2011 autofs-5.0.6
 -----------------------
diff --git a/autofs.spec b/autofs.spec
index 82edd1e..510ef76 100644
--- a/autofs.spec
+++ b/autofs.spec
@@ -57,7 +57,7 @@ inkludera n
 echo %{version}-%{release} > .version
 
 %build
-CFLAGS="$RPM_OPT_FLAGS -Wall" ./configure --libdir=%{_libdir} --disable-mount-locking --enable-ignore-busy --with-libtirpc
+CFLAGS="$RPM_OPT_FLAGS -Wall" ./configure --libdir=%{_libdir} --disable-mount-locking --enable-ignore-busy --with-libtirpc --disable-mount-move
 CFLAGS="$RPM_OPT_FLAGS -Wall" make initdir=/etc/rc.d/init.d DONTSTRIP=1
 
 %install
diff --git a/configure b/configure
index b5a3608..76b6d86 100755
--- a/configure
+++ b/configure
@@ -704,6 +704,7 @@ with_openldap
 with_sasl
 enable_ext_env
 enable_mount_locking
+enable_mount_move
 enable_forced_shutdown
 enable_ignore_busy
 '
@@ -1326,6 +1327,7 @@ Optional Features:
   --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
   --disable-ext-env	  disable search in environment for substitution variable
   --disable-mount-locking disable use of locking when spawning mount command
+  --disable-mount-move    disable use of mount move when when preparing tree of mounts
   --enable-force-shutdown enable USR1 signal to force unlink umount of any
 			  busy mounts during shutdown
   --enable-ignore-busy	  enable exit without umounting busy mounts during
@@ -5349,6 +5351,22 @@ $as_echo "#define ENABLE_MOUNT_LOCKING 1" >>confdefs.h
 fi
 
 #
+# Disable use of mount move
+#
+# Check whether --enable-mount-move was given.
+if test "${enable_mount_move+set}" = set; then :
+  enableval=$enable_mount_move;
+else
+  enableval=yes
+fi
+
+if test x$enable_mount_move = xyes -o x$enableval = xyes; then
+
+$as_echo "#define ENABLE_MOUNT_MOVE 1" >>confdefs.h
+
+fi
+
+#
 # Enable forced shutdown on USR1 signal (unlink umounts all mounts).
 #
 # Check whether --enable-forced-shutdown was given.
diff --git a/configure.in b/configure.in
index 46de65a..d3e4e54 100644
--- a/configure.in
+++ b/configure.in
@@ -324,6 +324,16 @@ if test x$enable_mount_locking = xyes -o x$enableval = xyes; then
 fi
 
 #
+# Disable use of mount move
+#
+AC_ARG_ENABLE(mount-move,
+[  --disable-mount-move    disable use of mount move when when preparing tree of mounts],,
+	enableval=yes)
+if test x$enable_mount_move = xyes -o x$enableval = xyes; then
+	AC_DEFINE(ENABLE_MOUNT_MOVE, 1, [Disable use of mount move when preparing tree of mounts])
+fi
+
+#
 # Enable forced shutdown on USR1 signal (unlink umounts all mounts).
 #
 AC_ARG_ENABLE(forced-shutdown,
diff --git a/daemon/automount.c b/daemon/automount.c
index 4f3151f..6bb5aa8 100644
--- a/daemon/automount.c
+++ b/daemon/automount.c
@@ -1743,9 +1743,20 @@ static void show_build_info(void)
 	count = 22;
 #endif
 
+#ifndef ENABLE_MOUNT_MOVE
+	printf("DISABLE_MOUNT_MOVE ");
+	count = count + 19;
+#endif
+
 #ifdef ENABLE_FORCED_SHUTDOWN
 	printf("ENABLE_FORCED_SHUTDOWN ");
 	count = count + 23;
+
+	if (count > 60) {
+		printf("\n  ");
+		count = 0;
+	}
+
 #endif
 
 #ifdef ENABLE_IGNORE_BUSY_MOUNTS
diff --git a/include/config.h.in b/include/config.h.in
index 4a3a990..97a8d2d 100644
--- a/include/config.h.in
+++ b/include/config.h.in
@@ -12,6 +12,9 @@
 /* Disable use of locking when spawning mount command */
 #undef ENABLE_MOUNT_LOCKING
 
+/* Disable use of mount move when preparing tree of mounts */
+#undef ENABLE_MOUNT_MOVE
+
 /* define if you have E2FSCK */
 #undef HAVE_E2FSCK
 
diff --git a/modules/mount_nfs.c b/modules/mount_nfs.c
index 8b567d2..7eab728 100644
--- a/modules/mount_nfs.c
+++ b/modules/mount_nfs.c
@@ -163,11 +163,6 @@ int mount_mount(struct autofs_point *ap, const char *root, const char *name, int
 	if (root[len - 1] == '/') {
 		len = snprintf(fullpath, len, "%s", root);
 	} else if (*name == '/') {
-		/*
-		 * Direct or offset mount, name is absolute path so
-		 * don't use root (but with move mount changes root
-		 * is now the same as name).
-		 */
 		len = sprintf(fullpath, "%s", root);
 	} else {
 		len = sprintf(fullpath, "%s/%s", root, name);
diff --git a/modules/parse_sun.c b/modules/parse_sun.c
index 021850d..13b8af8 100644
--- a/modules/parse_sun.c
+++ b/modules/parse_sun.c
@@ -1028,6 +1028,7 @@ static int parse_mapent(const char *ent, char *g_options, char **options, char *
 	return (p - ent);
 }
 
+#ifdef ENABLE_MOUNT_MOVE
 static int move_mount(struct autofs_point *ap,
 		      const char *mm_tmp_root, const char *mm_root,
 		      unsigned int move)
@@ -1063,6 +1064,7 @@ static int move_mount(struct autofs_point *ap,
 
 	return 1;
 }
+#endif
 
 static void cleanup_multi_root(struct autofs_point *ap, const char *root,
 					 const char *path, unsigned int move)
@@ -1145,6 +1147,7 @@ static void cleanup_multi_triggers(struct autofs_point *ap,
 	return;
 }
 
+#ifdef ENABLE_MOUNT_MOVE
 static int check_fstype_autofs_option(const char *options)
 {
 	char *tok, *tokbuf;
@@ -1171,24 +1174,27 @@ static int check_fstype_autofs_option(const char *options)
 
 	return found;
 }
+#endif
 
 static int mount_subtree(struct autofs_point *ap, struct mapent *me,
 			 const char *name, char *loc, char *options, void *ctxt)
 {
 	struct mapent *mm;
 	struct mapent *ro;
-	char t_dir[] = "/tmp/autoXXXXXX";
-	char *mnt_tmp_root, *mm_root, *mm_base, *mm_key;
+	char *mm_root, *mm_base, *mm_key;
 	const char *mnt_root, *target;
 	unsigned int mm_root_len, mnt_root_len;
 	int start, ret = 0, rv;
-	unsigned int move;
+	unsigned int move = MOUNT_MOVE_NONE;
+#ifdef ENABLE_MOUNT_MOVE
+	char t_dir[] = "/tmp/autoXXXXXX";
+	char *mnt_tmp_root = NULL;
+#endif
 
 	rv = 0;
 
 	mm = me->multi;
 	mm_key = mm->key;
-	move = MOUNT_MOVE_NONE;
 
 	if (*mm_key == '/') {
 		mm_root = mm_key;
@@ -1202,7 +1208,10 @@ static int mount_subtree(struct autofs_point *ap, struct mapent *me,
 	}
 	mm_root_len = strlen(mm_root);
 
-	mnt_tmp_root = NULL;
+#ifndef ENABLE_MOUNT_MOVE
+	mnt_root = mm_root;
+	mnt_root_len = mm_root_len;
+#else
 	if (ap->flags & MOUNT_FLAG_REMOUNT) {
 		mnt_root = mm_root;
 		mnt_root_len = mm_root_len;
@@ -1213,6 +1222,7 @@ static int mount_subtree(struct autofs_point *ap, struct mapent *me,
 		mnt_root_len = strlen(mnt_root);
 		mnt_tmp_root = (char *) mnt_root;
 	}
+#endif
 
 	if (me == me->multi) {
 		/* name = NULL */
@@ -1238,11 +1248,13 @@ static int mount_subtree(struct autofs_point *ap, struct mapent *me,
 			}
 			ro_len = strlen(ro_loc);
 
+#ifdef ENABLE_MOUNT_MOVE
 			if (!(ap->flags & MOUNT_FLAG_REMOUNT)) {
 				move = MOUNT_MOVE_OTHER;
 				if (check_fstype_autofs_option(myoptions))
 					move = MOUNT_MOVE_AUTOFS;
 			}
+#endif
 
 			tmp = alloca(mnt_root_len + 1);
 			strcpy(tmp, mnt_root);
@@ -1266,7 +1278,9 @@ static int mount_subtree(struct autofs_point *ap, struct mapent *me,
 				goto error_out;
 			}
 		} else if (rv <= 0) {
+#ifdef ENABLE_MOUNT_MOVE
 			move = MOUNT_MOVE_NONE;
+#endif
 			ret = mount_multi_triggers(ap, me, mm_root, start, mm_base);
 			if (ret == -1) {
 				error(ap->logopt, MODPREFIX
@@ -1279,11 +1293,21 @@ static int mount_subtree(struct autofs_point *ap, struct mapent *me,
 		int loclen = strlen(loc);
 		int namelen = strlen(name);
 
+#ifndef ENABLE_MOUNT_MOVE
+		/*
+		 * When using move mount to mount offsets or direct mounts
+		 * the base of the tree can be the base of the temporary
+		 * mount point it needs to be the full path when not moving
+		 * the mount after construction.
+		 */
+		mnt_root = name;
+#else
 		if (!(ap->flags & MOUNT_FLAG_REMOUNT)) {
 			move = MOUNT_MOVE_OTHER;
 			if (check_fstype_autofs_option(options))
 				move = MOUNT_MOVE_AUTOFS;
 		}
+#endif
 
 		/* name = mm_root + mm_base */
 		/* destination = mm_root + mm_base = name */
@@ -1303,7 +1327,9 @@ static int mount_subtree(struct autofs_point *ap, struct mapent *me,
 		} else if (rv < 0) {
 			char *mm_root_base = alloca(strlen(mm_root) + strlen(mm_base) + 1);
 	
+#ifdef ENABLE_MOUNT_MOVE
 			move = MOUNT_MOVE_NONE;
+#endif
 
 			strcpy(mm_root_base, mm_root);
 			strcat(mm_root_base, mm_base);
@@ -1318,6 +1344,7 @@ static int mount_subtree(struct autofs_point *ap, struct mapent *me,
 		}
 	}
 
+#ifdef ENABLE_MOUNT_MOVE
 	if (!move_mount(ap, mnt_root, target, move)) {
 		cleanup_multi_triggers(ap, me, mnt_root, start, mm_base);
 		cleanup_multi_root(ap, mnt_root, mm_root, move);
@@ -1326,6 +1353,7 @@ static int mount_subtree(struct autofs_point *ap, struct mapent *me,
 
 	if (mnt_tmp_root)
 		rmdir(mnt_tmp_root);
+#endif
 
 	/* Mount for base of tree failed */
 	if (rv > 0)
@@ -1341,8 +1369,10 @@ static int mount_subtree(struct autofs_point *ap, struct mapent *me,
 	return rv;
 
 error_out:
+#ifdef ENABLE_MOUNT_MOVE
 	if (mnt_tmp_root)
 		rmdir(mnt_tmp_root);
+#endif
 
 	return 1;
 }